How to Plant Dahlias in Containers

Dahlias' scientific name is Dahlia pinnata. Dahlias are a native, central Mexico plant that is found growing in volcanic soils. They like full sunlight but will tolerate light shade. Dahlias start to bloom in midsummer until just after the first frost. Dahlia blossoms come in a variety of colors except shades of true blue.

Things You'll Need

• Plantinh pot
• Bleach
• Compost
• Potting soil
• Wire mesh screen
• Dahlia plants

Instructions

1. Wash your planting pot with hot, soapy water. Rinse it with a mixture of one part bleach to nine parts water. This is especially important for used pots. Washing it kills plant diseases, organisms and pests.

2. Mix one part of well-rotted compost or manure with four parts of potting soil. Dahlias are heavy feeders and appreciate soil that has an abundance of organic materials. The compost will provide a slow release of nutrients to the dahlias as they grow and bloom.

3. Place a piece of wire mesh screen in the bottom of your pot over the drainage holes. This will keep the soil in the container and allow the water to drain freely.

4. Fill the pot halfway with your soil mixture. Place the dahlia plants on top of the soil. Pile a little soil up around each plant to hold them in place.

5. Fill the rest of the container with the soil mixture one to two inches from the rim. This allows room for the water to pool on top of the soil.

6. Gently press the soil down around the plants. Water your dahlias to settle the soil. Drain well and move to an area of bright light.

Tips & Warnings

• Plant a five-foot bamboo stake in the middle of the container if you are planting one of the tall varieties of dahlias. Once the plants grow tall enough to need support, loosely tie the dahlias to the bamboo stake. Dahlias usually start flowering in July. Cut the blossoms when they are fully opened if you are going to use them as cut flowers. Use sharp shears or a sharp knife to minimize the damage. Change the water every two to three days in the vase to extend the life of the cut blossoms.

• Dahlias are fast-growing, succulent plants that have big water requirements. The soil needs to be kept moist, not soggy. Dahlia roots suffer if there is too much water because it reduces the amount of oxygen to the roots. During hot weather, your dahlias may need to be watered twice a week.

References

• The Garden Primer; Barbara Damrosch; 2008
• University of Minnesota Extension: Growing Dahlias